Purification and properties of trypsin-like enzyme from the midgut of Morimus funereus (Coleoptera, Cerambycidae) larvae
Trypsin-like enzyme (TLE) from the anterior midgut of Morimus funereus larvae was purified by anion exchange chromatography and gel filtration chromatography and characterized. Specific TLE activity was increased 322-fold by purification of the crude midgut extract. The purified enzyme had a pH optimum of 9.0 (optimum pH range 8.5-9.5) and temperature optimum of 45 degrees C with the K(M) ratio of 0.065 mM for benzoyl-arginine-p-nitroanilide (BApNA). Among a number of inhibitors tested, the most efficient was benzamidine (K(I) value of 0.012 mM, Ic(50) value of 0.204 mM) while inhibition of TLE activity by SBTI, TLCK, and PMSF was partial. Almost all divalent cations tested enhanced the enzyme activity, amongst them Co2+ and Mn2+ stimulated TLE activity for 2.5 times. The purified TLE (after gel-filtration on Superose 12 column) had a molecular mass of 37.5 kDa with an isoelectric point over 9.3. Sodium dodecylsulphate-polyacrylamide gel electrophoresis (SDS-PAGE) revealed one band of 38 kDa, suggesting that the enzyme is a monomer.
Available from: Miroslava T Vujcic
- "In many ways captive breeding and resource restoration have to go hand in hand. M. funereus is a also a good model for the study of the impacts of various types of stress on insect metabolism (Ivanovicét al. 1975; Stanicét al. 1985; Nenadovicét al. 1986; Ivanovic´1991; Jankovic´-Hladni et al. 1992; Ðord¯evicét al. 1999; Lekovicét al. 2001) and for purification and characterization of digestive enzymes (Božicét al. 2008; Dojnov et al. 2008; Lončar et al. 2010). Recent papers suggest great plasticity of M. funereus larvae, therefore, it is anticipated that M. funereus can be captively bred. "
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ABSTRACT: Captive breeding has been suggested as a method of conservation for many vertebrates, and is increasingly being proposed as a strategy for invertebrates. In this study, the growth, development and fertility of adults of the vulnerable cerambycid Morimus funereus reared in captivity are examined. Two oviposition cycles; from May to September and from January to March were studied and larvae from wild adults and from the progeny of captive adults (second generation larvae) were examined. Five to 12 instars were observed during larval development. Larval development was completed in 218 days (average) for the progeny of wild adults with an average mortality rate of 10.3% and in 226 days (average) for larvae from captive adults with mortality rate of 34.9%. First generation larval body weights were disparate during development, while second generation larvae had similar weights with no significant differences. In this study we have tested the potential of captive breaded M. funereus larvae as a model for investigation of digestive enzymes. Amylase from the midgut of larvae reared under laboratory conditions showed twofold higher specific activities with a decreased number of isoforms expressed, as compared to the enzyme from field-collected larvae. Captive breeding of M. funereus can be used in the future as a part of an effective conservation strategy for this rare insect species.
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ABSTRACT: Two proteins with fibrinolytic activity were partially purified from yellow mealworm (Tenebrio molitor) by ammonium sulfate precipitation between 30 and 70% saturation, gel filtration on Sephacryl-S200-HR, ion exchange chromatography on DEAE-Sepharose-FF and metal chelate on Cu–HiTrap–IMAC–FF, but the enzymes had not been completely separated from each other. The two partially purified fibrinolytic enzymes were designated as TMFE-I and TMFE-II (Tenebrio molitor fibrinolytic enzyme) with molecular weights of 27.5 and 24.9 kDa by SDS-PAGE individually. The partially purified solution of TMFE-I and TMFE-II was considerably stable in the range of pH 5–10 and characterized by pH optimum of the enzymatic activity at 8.0. Thermal stability of TMFE was excellent at 45°C and below. The K
M value was 0.26 mM for amidolysis of Bz–Arg–pNA. According to inhibitor analysis by fibrin plate method, phenylmethylsulfonyl fluoride and tosyl-lysine chloromethyl ketone inactivated TMFE almost completely, but trans-(epoxysuccinyl)-l-leucylamino-4-guanidinobutane (E-64) and EDTA had little effect on their fibrinolytic activity. According to metal ion analysis by fibrin plate method, the effect of metal ions on activity of TMFE showed a great difference. Na+, K+ and Zn2+ had little effect on the activity of TMFE. Mg2+ and Cu2+ showed inhibition effect on the fibrinolytic activity of TMFE, but Ca2+ increased the fibrinolytic activity of TMFE at final concentration varying from 0 to 30 mM.
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ABSTRACT: The influence of diet composition - two substrates, wheat bran and sawdust - on isoform expression of digestive enzymes (cellulase, amylase and peptidase) in the midgut of Morimus funereus larvae was examined. Their impact on larval development was demonstrated by measuring the increase of larval weight during development and by analysis of digestive enzymes zymographic profiles, where the expression of cellulase isoforms from M. funereus larvae midgut has been examined for the first time in this study. Larvae reared on wheat bran had higher body weight between day 60 and day 100 than larvae reared on sawdust; however, both groups achieved similar body weight after day 110. Wheat bran as substrate induced different cellulase and amylase isoforms. Oak sawdust in substrate acted as inducer of peptidases. The highest cellulase activity and the greatest isoform variability were detected in the midgut extracts of larvae reared on wheat bran. From our results it can be assumed that M. funereus endocellulase, amylase and peptidase are secreted in the anterior midgut, and their concentration gradually decreases towards the hindgut.
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